We have recently, under tenure of National Cancer Institute Research Grant CA12920, obtained definitive results which implicate carbohydrate-containing molecules in the intercellular adhesion of a wide variety of vertebrate cell types. L-glutamine appears to function in intercellular adhesion by transaminating fructose-6-phosphate, yielding D-glucosamine-6-phosphate, the key intermediate in the formation of carbohydrate-containing molecules involved in intercellular adhesion. Using an extremely quantitative electronic particle counter assay to measure rates of adhesion we are continuing our efforts to determine the nature of specific chemical groups which function in cell adhesion by a variety of approaches: use of polyene antibiotics isolation and purification of molecules which promote ascites tumor cell adhesion, examination of cells for specific activity of glutamine synthetase and how this correlates with adhesiveness, use of plant lectins to determine the display and functional roles of cell surface carbohydrates and use of hapten inhibitors of cellular adhesion. Some of this work has been completed. The remainder is in progress. In addition to the above results, we have found that the ascites tumor cells examined lack the enzyme glutamine synthetase. This finding may account for their requirement for exogenously supplied L-glutamine needed to form the molecules involved in their adhesion to each other.